This invention relates to systems used for signature verification and more particularly to improvements therein.
Human action patterns, in contrast to machine generated patterns, have a relatively large degree of variability. Thus although various patterns such as heart patterns, walking patterns or signatures, may be considered as characteristic of an individual, they do vary from one performance to another. A human examining signatures for verification can consciously allow for small variations in a person's signature. However, for a machine-based verification system, a method is required which, although automatic, can similarly allow for some specifiable range of variability.
Correlation is a well-known analytic technique for comparing the likeness of two signals. The presently favored technique for handwriting verification is to correlate a handwritten signature against a stored template signature. The problem arises however, as to how best to correlate, for example, a more rapidly-written signature against a more slowly-written signature or vice versa. Correlation in these instances is not very good. Another problem arises when, for example, a person writes two words, such as his first and last name, at different speeds. Some correlation technique should be provided to allow for these "human" variations, and yet which is sufficiently accurate to separate a valid signature from a forgery.